Nomenclature, Microorganism Size,
Microorganism Shape, Gram Staining
Nomenclature
• The nomenclature was established by Carolus Linnaeus (1735)
• The name of each organism is split into 2parts: the genus and species. for example: Escherichia
coli.
• It is written in italics or underlined.
• To make it easier after using the full name in a document the genus can be abbreviated.
• In the case of Escherichia coli, it is abbreviated to E. coli.
Size of Microorganisms
Dimensions Visible to naked Microscope
(Typical) eye
1-10µm Light
Bacteria NO
(10-6m)
Yeast <5-50µm SOME Light
Moulds µm - mm YES Light
Microalgae 5µm – 1mm SOME Light
Protozoa 10 – 150µm SOME Light
<20-300nm
Viruses NONE Electron
(10-9m)
Microorganism Shape, Gram Staining
Nomenclature
• The nomenclature was established by Carolus Linnaeus (1735)
• The name of each organism is split into 2parts: the genus and species. for example: Escherichia
coli.
• It is written in italics or underlined.
• To make it easier after using the full name in a document the genus can be abbreviated.
• In the case of Escherichia coli, it is abbreviated to E. coli.
Size of Microorganisms
Dimensions Visible to naked Microscope
(Typical) eye
1-10µm Light
Bacteria NO
(10-6m)
Yeast <5-50µm SOME Light
Moulds µm - mm YES Light
Microalgae 5µm – 1mm SOME Light
Protozoa 10 – 150µm SOME Light
<20-300nm
Viruses NONE Electron
(10-9m)
